When Dmitry Argarkov was sent a letter offering him a credit card, he found the rates not to his liking.

But he didn't throw the contract away or shred it. Instead, the 42-year-old from Voronezh, Russia, scanned it into his computer, altered the terms and sent it back to Tinkoff Credit Systems.

Mr Argarkov's version of the contract contained a 0pc interest rate, no fees and no credit limit. Every time the bank failed to comply with the rules, he would fine them 3m rubles (£58,716). If Tinkoff tried to cancel the contract, it would have to pay him 6m rubles.

Tinkoff apparently failed to read the amendments, signed the contract and sent Mr Argakov a credit card.

...

Earlier this week a Russian judge ruled in Mr Argakov's favour. Tinkoff had signed the contract and was legally bound to it. Mr Argakov was only ordered to pay an outstanding balance of 19,000 rubles (£371).